Locomotive fire box equipment



Oct. 19, 1937. H. w. SNYDER LOEOMOTIVE FIRE BOX EQUIPMENT 3 Sheets-Sheet 1 Filed March 5, 1934 W W M UUU Q J J Q Q 0 e Kw R R \Q Kw eQ m w a w m I w k N M k w .& .Q a o G 0 OMskN 7 w R un l l hhhhh Oct. 19, 1937. H. w. SNYDER v LOCOMOTIVB FIRE BOX EQUIPMENT Filed March 5, 1934 3 Sheets-Sheet; 2

Oct. 19, 1937. H, w YDER 2,096,439

LOCOMQTIVE FIRE BOX EQUIPMENT Filed March 5, 1934 3 Sheets-Sheet 5 Patented Oct. 19, 1937 cm-ED STATES PATENT OFFICE 24 Claims.

This invention. relates tofire-box or furnace equipment, which, while adaptable to various fiields, is, especially advantageous and suitable.

This invention, contemplates the preheatingv of combustion air and delivering such air through the vfire bed supported by thejgrates at the bottom of the fire-box. Thepreferred form of air preheater equipment employedin accordance with this invention is arranged to utilize a source of exhaust steam on the locomotive, usually the cylinders, asthe heating medium during at least a portionof the timelthe equipment is, in operation.

Still further the invention has in View employing exhaust steam from the cylinders of the locomotive when the engine is working, and then :5 switching to a difierent source of heating medium during periods when the engine is not working.

The invention, therefore contemplates, a' material'increase in efficiency of operation, especially from the standpoint of fuel consumption, and

$3 I have found that even though exhaust steam from the cylinders is only intermittently available, yet when the arrangements of this invention are employed, including the air heater structure to-be described more fully hereinafter, a

drop in fuelconsumption of from- 8 to 9% and even higher may be obtained.

The invention is also concerned with a problem relating rather to maintenance of equipment'than to eiliciency of combustion, which 40 problem can probably be understood to better advantage after a consideration of some'of the structuraband'operating conditions of modern locomotive practice.

With the increase in size, weight and power of locomotives, the fire-boxes, ofcourse, are correspondinglyincreasedin size. These large boxes also require side sheets of great length. The sidesheets," each of which 'isnormally formed or single-metal sheet, have been subject to crackingand warping, particularly in the larger locomotives, with the result that considerable difficulty ande-xpense has been encountered in replacements orrepairs. Apparently, the cracking and warping has been 'due primarily to irregular thermal expansion and contraction in different portions or areas of the side sheets. I have found that the irregularities in expansion and contraction are ordinarily caused by admission of air to the fire-box at different temperatures in different regions thereof, especially during idle periods of the locomotive. In such idle periods, the the bed frequently develops thin or relatively dead spots and these often appear along the sides of the fire-box adjacent to the side sheets. titles of relatively cold air have been admitted from time to time through these thin or dead spots and this has caused irregularities in the temperatures to which the side sheets are subjected. In consequence, of course, the side sheets expand and contract in a similarly irregular manner. Furthermore, in ordinary locomotive practice, especially as contrasted with stationary power plant operation, the temperature of the air admitted through the fuel bed even under L normal conditions varies over a wide range, since the air is directly admitted at the outside atmospheric temperature which may be, for example, -20 F. or F.

The present invention at least in large part 2 normal operating conditions; also when the 1000- motive is standing idle or is drifting, as well as when it is running under power.

A more specific object of the invention is the provision of a novelpreheawr arrangement including heater elements which are mounted in the air intake openings of the ash pan, preferably along one or more lower edges of the fire-box below the grates.

Another object involves a novel construction and arrangement of heater elements for the purpose of providing a high degree of efficlency in heat transfer. At the same time, these elements are further constructed and disposed in a way to prevent hot coals from dropping out of the ash pan through the air intake openings, this being of importance in avoiding fires.

The invention is also of advantage in providing a system for supplying and controlling the heating medium used in the preheater elements, which system is arranged so that these elements employ exhauststeam derived from auxiliaries or the cylinders or both, when the auxiliaries or the cylinders are working, and from the steam space of the boiler When the auxiliaries or cylinders are As a result considerable quan- 7 lowing description making reference to the accompanying drawings, in which Figure 1 is a somewhat diagrammatic side ele' vational view of a locomotive, with the air preheater arrangement of the present invention,

appliedto the fire-box thereof;

Figure 2 is a view similar to Figure 1 showing a modified system forcontrol and supply of the heating medium;

Figure 3 is a side-elevational view on a considerably enlarged scale of a portion of a fire-box with part of the mechanism of this invention applied; V

Figure 4 is a transverse sectional view of the structure appearing in Figure 3, the section being taken through different parts of the heater mechanism at opposite sides of the fire-box, in accordance with section lines 4a4a and ib -4b appearing on Figure 3; V Figure 5 is a still further enlarged fragmentar sectional view of certain heater parts taken. substantially as indicated by the line 55 on Figure 4, with portions omitted for the sake of clarity; Figure 6 is a fragmentary view illustrating a modified control system for the heating medium;

Figure 7 is a sectional View of a valve mechanism employed in the control system of Figure 2;

and a Figure 8 is a sectional View of one of the valve devices employed in accordance with the arrangement of Figure l. V

In the general layouts of Figures 1 and 2, the locomotive boiler is designated by the letter A, the

cab at B, the fire-box at C, the main driving cyl-- inders at D and the tender at E; Furthermore, in these views the letter F indicates, in general, the heater elements which are applied along the lower edge of the fire-box at each side of the locomotive.

Before considering the construction, mounting arrangements and operation of the air preheater elements, attention is called to the control and with a manual shut-off valve M in advance of which the supply pipe is divided into two branches l3a and 13b. The latter of these branches is extended forwardly to communicate with the exhaust cavity or passage of the cylinder orcylinders D. Branch 13a is extended to some source of live steam such as the turret i5 and controlled by a manual shut-off valve I6. This branch is also provided with a valve device I! which is controlled by the actuating lever [23, connected with the throttle rod I I by link I9 and the attachment device 29.

The steam supply pipe to the: heater elements is shown at l3 and isprovided locomotive is in operation, the exhaust steani' of the cylinders, passingrearwardly through V branch [3b, is employed as theheating medium:

in the heaterelementsF. Valve "is coupled with the throttle control, as by connectionwith the throttle rod H in the manner referred to above, andthis valve serves to open the branch [3a when the main throttle is closed by the lever 9 at which time steam .is no longer available in the exhaust cavities of the cylinders D.

The construction and operation of valve l'l,

will be apparent from inspection of Figure 8 in which it will be seen that the operating arm' 7 I8 is pivotally mounted on the valve casing at 2|.

The lower end of this arm is adapted to contact with the push rod 22 constituting the stem of valve 23. Valve 23 closes the port be. tween chambers 24 and 25, the former 'of which is connected by the upper portion of branch I341 with the turret l5 and the latter of which is connected by. the lower portion of branch- I31;

with'the supply pipe l3 extended to the heater,

The steam pressure from turret; 15, therefore; serves to urge the valve'toward'its closed position and in addition this action may be supplemented by a spring 26.

In'the preferred adjustment and arrangement:

of the valve l1 and theconnections extended to the throttle lever, l i, the valve is opened by'the final closing movement of the throttle lever! ments are provided with their. heating medium from the turret [5, it being understood, of course, that this latter steam supply may be obtained from any desired source on the locomotive., To.

ensure the above operation, a, gap is preferably;

left between valvelstem 22 (Fig. 8) and lever 18,. when the locomotive throttleisin the wide open position. i w

With a view to preventing the turret to the exhaust passages of the cylinders through branch I31), I preferablyemploy a checkvalve in line l3b which is indicated at 21' in Figure 1. It willthus also be seen that I have provided (in the valve 21) an automatic means of closing the exhaust steam line when the motive cylinders are not working. 7 1

. With further reference to the general layout of Figure 1, the exhaust from the heater F may flow of steam from I be discharged directly to the track or, as shown a in the drawings, the exhaust may be delivered through pipe 28 into a steam trap 29 after which the condensate may be conducted through connection 30 provided with check valve 3l to the Water space of the tender E by any suitable or.

desired means. The exhaust and condensate ar rangements shown in Figure 2 are the same as 60 those just mentioned.

Turning now to the control and supply system for the heater, as incorporated in the modification of Figure 2, the supply pipe J3 with its with valve 32 with which pipes 33 and also communicate. 'Pipe 33 is exten'ded to the turret;

[5 or other suitable live steam source and may be provided with a shut-off valve [6, as in Figure 1.

The forwardly extending, connection '34 prefer I: i: ably communicates with the main steam supply to the cylinders D beyond the main throttle; For example, this connection 34 may be coupled with the steam pipe .4 portion of :whichis shown at 35 in Figure 2. vPipe 34, thereforeywillcarry pressure only whenzthe main throttle is open; and the valve 32 is of the type which, in the absence of pressure in'line 34, opens communication from pipe 33 to the branch l3aiand closes this'communication upon the admission of pressure from pipe 34. V, I I 1 'While valves of several different types might possibly be employed forthe purpose, I prefer to use thevalve device illustrated in Figure '7 in which it will be seen that the pipe 33 may be coupled with pipe I300v when the valve 32a is unseatedr It'will be'noted 'that valve 32a is so positioned "with respecttoits seat that, in the absence of pressure in connection 34, the pressure in line 33 will openithe valve and thus and-3 2c carries the valve to a position in which the valve element 32a closes its seat.

With further reference to this valve device, it should be noted that the valve part 3217 closes communicationbetweenthe:pipe 34 and the live steam passage to'which pipe 13a is coupled and thus prevents flow of steam from the dry pipe into the air preheater elements. When the valve is in the right-hand position, i. e.,* when the valve element 32a is unseated, the portion 320 serves to close the chamber with which pipe 34 connects.

It willbe seen, therefore, that this system automatically shifts the steam source employed in the air heater from the exhaust steam of the cylinders D to the live steam of the turret l5, the

latter, of course," being employed when the throttle lever 9 is closedfand the pressure, therefore, reduced in the dry pipe 35. In the scheme of Figure 2 a check valve 2'! also appears in the forwardly extending branch 13b, this being for the purposesalready mentioned .With respect to the showing of both of the arrangements described, it might be noted that the throttle lever in each of. Figures 1 and 2 is illustrated in open position. Valve ll of the arrangement of Figure 1, (shown in detail in Fig. 8) is,

therefore, in closed position; Still further, both systems contemplate the-use of a'blower fitting 36 interposed in the supply line extended from the turret l5 beyond the shut-01f valve l6 therein,

this fitting being provided, for the purpose of mechanism 32 under the influence of pressure admitted on the right-hand side 320 of the valve 32?), through the pipe 34'. Fora similar purpose, the valve parts 321) and 320 may be made of larger diameter than the valvepart 32a. i

With a view to positively preventing entrance of steam into the air heater elements at full boiler pressure, the systems of Figure l and Figure2, as well as of Figure-6. to be described hereinafter,

contemplate the use of a safety valve 64 in the supply pipe [3, as shown.

With regard to the control system of Figure 1, it might be mentioned that this arrangement is of advantage in providing a positive mechanical means of closing the steam supply line from the turret to the heater when the main throttle is opened; and vice versa. This particular arrangement is well adapted to locomotives having an external throttle rod connection to the main throttle. On the other hand, the system of Figure 2 is particularly adapted to locomotives in which an internal throttle connection is employed. Furthermore, the scheme of Figure 2 provides an entirely automatic means of controlling the supplemental steam supply from the turret, this being accomplished by the valve device 32 which is under the influence of pressure in the main steam supply pipe extended to a cylinder or cylinders.

The still further modified layout of Figure 6 isofadvantage for a number of reasons including its simplicity and the fact that, according to this scheme, if it be desired to supplement the exhaust steam available with steam from the turret, this may be done by opening the manual valve 65. This valve is positioned for convenient access in the cab of the locomotive and replaces the valve device I! of Figure 1 and the valve device 32 of Figure 2, as will readily be apparent from inspection of Figure 6. The system of Figure 6, of course, also contemplates the employment of a blower fitting 3% and a reducing valve 37.

The arrangement and structure of the air heater elements appears in greater detail in Figures 3 to 5 inclusive, but before discussing the structure it might first be mentioned that in accordance with this invention it is of importance to arrange the heater equipment so as to deliver the preheated combustion air upwardly through, the grates and the fire bed. With this in mind, as shown in Figures 1 and 2 the heatersor heater assemblies are arranged at the lower edges of the fire-box. In the side elevation and transverse section of Figures 3 and 4, respectively, a number of features of the supporting arrangement for g y the heater are illustrated. In these views the numeral 38 indicates the upper and gradually sloped portion of an ash pan, While 39 designates a lower part thereof which is normally provided with an ash door. Furthermore, as best seen in Figure 4, the ash pan and the heater devices F are preferably supported in association with each other as by means of the brackets or the like 40 which extend upwardly from the heaters inside of the side sheets 4| adjacent to the mud ring 42. The elements 4!] may be employed to position the side grate rails 43 as clearly shown. Additional support members.44 are arranged at the ends of the heaters, these being bolted to brackets 45 depending from the mud ring and having upwardly projecting elements 40 which also engage the side grate rails. The center or intermediate grate rails may be supported by means of brackets such as that shown at 66 toward the right of Figure 4. This bracket is carried on the top of the main frame cradle and projects up through the ash pan to provide pivotal support'for an addi-. tional member '81 which, as shown, is grooved or forked to embrace a center rail.

The ash pan may receive at least part of its support by the flanged portions 38a which may be attached to the heaters at the points shown in Fig. 4.

Although, insofar as many features of the in vention are concerned, the heaters: themselves I may take a 'variety' of forms, yet I prefer the cleaning the ash pan.

arrangement illustrated in the drawings. This construction is of a sectional type, there being two heater sections 46, 46a shown in Figures 1,2 and '3 which are mountedin end to end relation with an ash pan'investigation or clean-out box, 4'! interposed therebetween. As appears to best advantage in Figures 3, 4 and 5, the heater'sections are each comprised of a casing 48containing a multiplicity of tubes 49 which are preferably of the. finned type. These tubes are located relatively close together, and preferably in. staggered fashion'as appears at the left of Fig. 4 so as to provide maximum efi'iciency in heat transfer. The tubes extend'lengthwise through the heater section and terminate in tube sheets 50 'one of which appears in Fig. 5; It will also be seen that the fins lie in planes paralleling the general path of. the air in flowing through openings 5| and 52 into the heater and therethrough to be discharged just below the grate through apertures 53 (see Fig, 4)

In addition to the above I have found that theuse of finned tubes, especially in substantially the arrangement illustrated, constitutes a very effectivemeans .of' preventing hot coals from fall 'ing out'of the ash pan through the intake openings thereof. This is of importance in eliminating a fire hazard which has heretofore been rather troublesome.

' While separate steam supply and exhaust or condensate connections may be employed for each heater section, in the form of construction illustrated in the drawings the heating medium is introduced into the tubes 49 by means of a header 54 which is arranged at one end of one of the heater sections. At the other vend'of this section the tubes 49 discharge into a header chamber 5 5 which is formed as a part ofthe central box 41 provided foraccess to theyash pan. In Figures 3 and .4 it will be seen that this box is provided with a horizontal partition :56 below which a passage 51 is formed for the purpose of conducting steam from the header chamber to the additionalheader chamber 58 serving as. the inlet header for the tubes 49 of the second heater section 46a. Above the partition 56 is 'an additional chamber or passage 59\ nor.-

mally closed by the ash pan door 60 pivotally mounted at El so as to facilitate investigation or At the discharge end of the heater section 46a an additional header 62 is provided and this, i I of course, delivers into the condensate or exhaust pipe 28 hereinbefore mentioned.

:Thetype of heater mechanism described jus above is of considerable importance for a number of reasons including the fact that thesectio'nalized construction is very flexible and readily adapted'to a variety of conditions encountered in installation. The sectionalizing of the heater elements themselves permits usethereof at differentedges of the fire-.box and also facilitates malu'ng installations where different numbers of the sections are necessary at different sides of the box. It willalso be observed that the heater" sections, as well as at least some of the headers,

pan arrangements generally, it is pointed out i that the positioning and mountingv of these parts is all worked out with aview to preventing, as

faras-possible, the access of air to the fire bed ex' cept through the heater elements. .With this object in 'view the arrangement of the grates inthe fire-box and the support. thereof, especial- 1y the support of the side and intermediate rails,"

hasbeen' worked out so as to eliminate, iasl faras possible, apertures through orv around-the ash pan and in'this way to reduce to a' minimum the amount 'of;,air which may enter the. fire-box except through the heater'elem'ents.

W'hilethe heater units may be'variously disposed with relation to the sides, frontyor rear of the fire-box, the disposition'shown in Figures 1,

2 and 6, that is, closelyiparalleling the adjacent V side edges of themud ring andash pan, is espe-[ cially desirable, for severalreasons, including the.

following: first, for clearance purposes, since this location interferesleast with other parts of the the locomotive; second for inspection and replacement purposes, asis evident from the pre-i vious discussiony'third; for mounting and supporting purposes, as is also now clear; fourth for structural,purposes since the air is directly admittedthrough the. heater into the space beheath thegrates, with no extended air conduitsand with a minimum ofichange of existing locomotive structure;- :and fifth, foroperational pur-: poses, since this location, results in an inclined disposition of the heater. tubes, which, in conjunction with the illustrated location of the steam power plant layout including a steam generator with its furnace or fire-box and an intermittently operated steam consuming mechanism and provides, in such a layout,a means for preheating air admitted to the furnace .whichmeans' employs, as aheati ng'medium, theexhaust from the intermittently operated engine or the like.

Additionally, the arrangements of this invention provide for introduction of substantially unif formly preheated air to the fire-box even though the preheater equipment operates'in part on the i exhaust from theintermittently operated mecha nism, the heating medium being provided from' 7 some other source during those periods when the said mechanism is not working steam.

importance to ensure admission of preheatedair during periods of idleness or periods when the main cylinders' are'not receiving steam, and the invention is also of especial. advantage in meeting this condition since it incorporates means providing for the preheating 'of theair at the time 'As brought out hereinbefore, it is of especial when there is the greatest danger "of irregular 7 expansion and contractionof the side sheets and" thereforeof cracking or warping of these sheets.

It will also be apparent from the foregoing deheaters is of relatively simple construction and yet positive action. The control systems "are also advantageous in being entirely or 'a't least largely automatic and this is of importance in avoiding multiplication'of the controls which must'be attended by the engine crew.

I claim:- 3

1. In a steam locomotive having a fire-box or the like for combustion of fuel, means for sup-v scription and the drawings that the supply and control system} for'the steam employed in the porting a fuel bed for combustion therein, means for preheating the combustion air supplied to the fuel bed including heater elementsja source of 3 inlet and condensate outlet connections, results I flow of the condensate in i supply of a heating medium, conduit means for delivering the heating medium from said source to the heater elements, and control means automatically operative upon stopping the locomotive to open said conduit means.

2. In a'locomotive having'a furnace for its boiler, driving cylinders and. steam control means for the latter, a mechanism for heating the combustion air for the furnace including heater elements having air passages therethrough delivering into the furnace, conduit means for supplying a heating medium to the heater elements, a valve for controlling flow in the conduit means, and valve operating means connected with the steam control means for the driving. cylinders in such manner as to open said valve upon shutting for supplying live steam from the boiler to said .25

elements, and means for controlling the supply of steam to said elements, the fire-box, ash pan and air passages being arranged to provide for the flow of substantially all. the combustion air through the said passages transversely across said elements.

4. In a steam locomotive having driving cylinders and fire-box, means for supporting a' fuel bedin the fire-box, a mechanism for heating air admitted to the fuel bed including air heater elements arranged adjacent the bottom of the box for heating air as it'passes to the fuel bed, means for conducting exhaust steam from the cylinders to said heater elements for heating purposes when the locomotive is running, and means for supplying another heating medium to said elements whenthe locomotive cylinders are not receiving steam.

5.. In a steam locomotive having driving cylinders and fire-box; means for supporting a fuel bedin the fire-box, a mechanism for heating air admitted to the fuel bed including air heater elements arranged adjacent the bottom of the box for heating air as it passes to the fuel bed, means for conducting exhaust steam from the cylinders to said-heater elements for heating purposes when the locomotive is running: and means operative upon cutting off the supply of steam to said cylin ders for supplying anotherheating medium to said elements. 1 s

6. Inasteam locomotive having a boiler and boi-ler 'furnace, driving cylinders and steam controlling'means for the driving cylinders, grates for supporting a bed of fuel in the'furnace, a mechanism for heating air admitted tosthe fuel bed including heater elements with air passages therethrough delivering to the under side of the grates, means for supplying exhaust steam from said cylinders to said elementsfor heating purposes, and means operative upon shutting off of the steam supply to said cylinders by said control means for supplying an additional heating medium to the heater elements.

'7. Ina steam locomotivehaving a boiler and boiler furnace, driving cylinders and steam controlling means for the driving cylinders, grates for supporting a bed of fuel in the furnace, a mechanism for heating air admitted to the fuel bed including heater elements withair passages therethrough delivering to the under side of the grates, means for supplying exhaust steam from said cylinders to said elements for heating purposes, a supply line for an additional heating medium extended from a suitable source to the heater elements,-a valve in said line, and controlling means for said valve operatively connected with the steam control means for the driving cylinders and arranged to open said valve upon shutting off of the steam to said cylinders.

8. In a locomotive having a fire-box and driving cylinders with main steam passages associated with the cylinders, air heater elements associated with the fire-box and having air passages therethrough discharging the primary air of combustion to the fuel in the fire-box, a source of supply for a heating medium for said elements, a connection between said source and said elements having valve means therein, and means for controlling said valve means operative under the influence of pressure in said main steam passages.

9. In a locomotive having a fire-box and driving cylinders with main steam passages associated with the cylinders, air heater elements associated with the fire-box and having air passages therethrough discharging the primary air of combustion to the fuel in the fire-box, a source of supply for a heating medium for said elements, a connection between said source and said elements having valve means therein, and control mechanism for the valve means operative to close I the valve means upon a rise in pressure in said steam passages and to open the valve means upon a drop in pressure in said passages.

-10. In a locomotive having a fire-box and driving cylinders with main steam passages associated with the cylinders, air heater elements associated with the fire-box and having air passages therethrough for delivery of air to the fuel in the fire-box, a source of supply for a heating medium for said elements, a connection between said source and said elements, a connection for conducting exhaust steam from said cylinders to said heater elements, and control means for said connections operatively associated with said main steam passages for opening the connection from said source in the absence of appreciable pressure in the main steam passages and for closing the connection from said source upon a rise in pressure in said main steam passages.

l1. In a steam locomotive having a fire-box or the like for combustion of fuel, means for supporting a fuel bed for combustion therein, and driving cylinders with main steam passages associated therewith, means for preheating air supplied to the fuel bed including air preheater mechanism, a connection extending from the cylinders for conducting exhaust steam to the heater mechanism for heating purposes, a source of supply of another heating medium, a connection extended from said source to the heater mechanism with control means therefor, and means for preventing flow of heating medium from said source to the cylinders through the connection which extends from the cylinders, when the medium of said source is being employed in the heater mechanism.

12. In a locomotive having a fire-box and driving cylinders with main steam control mechanism therefor including a throttle and its actuating means, means for supporting a fuel bed in the fire-box, air preheater means delivering combustion air to the fuel bed, a source of supply of a heating medium, a connection extended between said source and the heater elements, and controlling means for said connection operatively 7 associated with the throttle.

actuating means for the 13; In a locomotive having afire-box and driving cylinders with main steam control mechanism therefor including a throttle and its actuating means, means for supporting a fuel bed in the fire-box, air preheater means delivering combustion air to the fuel bed, a source of supply of a heating medium, a connectio-n'extended between fire-box, air preheater means delivering com-' 1 exhaust steam from the cylinders said source and the heater elements, and controlling means for said connection including a valve therein and operating connections for the valve coupled with the throttle. a i

14. In a locomotive having a fire-box and driving cylinders with main steam control mechanism therefor including a throttle and its actuating means, means for supporting a fuel bed in the fire-box, a'ir preheater means delivering com bustion'air to the fuel bed, a source of supply of a heating medium, a connection extended between said source and the heater elements, and

controlling means for said connection including a valve therein and operating connections for the valve coupled with the actuating means for the throttle, the operating connections and said valve being'arranged to provide closure of the said connection when the throttle is opened and vice versa. i i i 15. In alocomotive having a fire-box and driv ing cylinders with main steam control mechanism therefor including a throttle and its actuating means, means for supporting a fuel'bed in the bustion air to the fuel bed, a source of supply of a heating medium, a-connection extended between said source and the heater elements, a source of supply of exhaust steam, a connection extended from the source last mentioned to the heater elements, controlling means for the first mentioned connection operatively associated with the actuating means for the throttle, and means for preventing fiow of medium from the source,

supply line for an additional heating medium extending from an additional source to the heater elements, a valve in said line, and controlling means for said valve operative upon actuation of said throttle and arranged to openlsaid valve upon closure of the throttle.

17. In a locomotive having driving cylinders and fire-box with means for supporting a fuel 7 bed therein, a mechanism for preheating cornbustion air including air heater elements arranged adjacent said means forheating air as it is supplied to the fuel bed, means for conducting to said heater elements for heating :purposes'when the locomotive is running, conduit means for supplying another heating medium to said elements, and control means for said conduit means au'tomatically operative to open the conduit means when the locomotive cylinders are not receiving steam.

actuating means for the I 18; In locomotivefire box equipment having an ash pan with air intake openings along the intake openings and including tubular heater ele-' ments having'finsthereon which elements and; their fins-are so arranged as to provide a multi-.

plicity .of relatively small air passages therebetween, whereby to-prevent or restrict hot coals or the like from falling out of the ash pan through o the intake openings. I 1 7 19.In'a locomotive having a boiler, a furnace for the boiler, grates in the furnace for supporting a fuel bed for purposes of combustion, air

passages for supplying the air of combustionto,

the fuelbed through the gratesfromthe under side thereof, and airipreheater means extended alongva side of the gratesinsaid passages and positioned adjacent to the grates for flow of-"air transversely; therethrough, whereby to discharge preheated airsubstantially directly to the under side of the grates.

'20. In combination with a steam generator and an intermittently operating steam m'o"tor,*appa- V V ratus for preheating the air for the'combustion .in the generator, means for delivering exhaust steam of the motor to said apparatus when-the motor is operating, means for delivering steam the motor into and out of operation, and means acting under the influence of said mechanism for effecting said change in steam delivery.

21. In a locomotive havinga 'fire-boxI-with grates therein and an' ash pan structure there below the latter of which is spacedorapertured;

to provide means. foradmitting combustion air to the under side of the grates means for pre-- I heating combustion air including tubular heater elements extended along and generally parallel to an edge ofthe-grates associated with an apertured portion 'of the ash pan, the said tubular v edges thereof, air preheater mechanism in the I from the generator' to said apparatus when the I i motor is not operating, mechanism for putting elements having .fins thereon positioned to pro-f .vide a multiplicity of passages extended generally transverse the tubular elements 'from the exterior of the ash pan through the apertured and means for supplying a, said tubular elements.

a portion thereof to the underside of the grates, heating medium to J 22. In a locomotive having a boiler, a combus tion chamber associated with the boiler andan intermittently operated steam motor, means for burning fuel in the combustion chamber, means i for preheating air supplied to the fuelQfor its primary combustion, means for delivering exhaust steam of the motor to the airrpreheating means ing means when the motor is not operating, and

mechanism for shutting off either of said deliv ery means when the other is deliveringsteam.

-23. In a locomotive having driving'cylinders, a boiler and a fire-box with'meansforburning fuel therein, means .for delivering steam from when the motor is operating, and'means fordelivering steamfrom the boiler to theiair preheat the boiler to said cylinders, preheater means for 7 the air of combustion delivered to the fire-box,

cylinders to the preheater to serve as a heating medium therein, a fluid pressure operated valve in said conduitfoperative to prevent back flow to said cylinders, and means for deliveringi fiuid pressure to said valve to close the'same,"the last -means being automatically operative to deliver fluid to the valve upon closureof the steam delivery means for. the cylinders. t

2e. Ina locomotive having a boiler, furnace a conduit for'passing exhaust steam {from the for the boiler, grates in the furnace for supporting a fuel bed for purposes of combustion, air passages substantially throughout the length of a side edge of the grates for supplying the air of combustion for the fuel bed through the grates from the under side thereof, and air preheater means extended along a side edge of the grates and substantially coextensive in length with said side edge, the air preheater means being disposed in said passages and positioned adjacent to the grates for flow of air transversely therethrough, whereby to discharge preheated air substantially directly to the under side of the grates substantially throughout the length of the side edge thereof.

HERBERT W. SNYDER. 

